BREAKING: Plea Agreement Reached in Cheyenne Murder Case [VIDEO]

A 22-year-old Cheyenne man charged in the November 2017 shooting death of a 19-year-old has accepted a plea agreement from the U.S. Attorney's Office.

Armando Ramirez-Serna pleaded guilty Tuesday in U.S. District Court to interference with commerce by robbery and use and discharge of a firearm during and in relation to a crime of violence causing death, admitting that he shot and killed Justin Robinson and took marijuana and cash out of his SUV.

In exchange for his plea, the government agreed to dismiss counts III and IV -- use and discharge of a firearm during and in relation to a crime of violence and use of fire to commit misprision of a felony -- during sentencing.

"This was a heinous crime," said Assistant U.S. Attorney Stuart Healy III, adding that Ramirez-Serna robbed Robinson of less than four ounces of marijuana and just over $200 to make a delinquent child support payment.

Healy said the plea agreement, which calls for a recommended sentence of 40 years, was reached over four weeks of discussion.

"We take this type of crime very seriously," said U.S. Attorney Mark Klaassen. "Obviously when you have a murder involved that's a particularly terrible and heinous crime, and so when we evaluate a sentence we want to make sure that justice is done."